The Italians are able to complete all 4 Francesco Caracciolo class fast battleships towards the end of World War One.
The POD would be false reports of the Austro-Hungarians making rapid progress building their Erstaz Monarch class. This leads to the British Government providing the Italians with the steel required to complete the ships or the money to buy steel from the USA.
The TTL WNT would allow Italy to keep the 2 Andrea Dorias and the 4 Caracciolo class, which would have come to about 171,000 metric tons.
IOTL they were allowed to keep 10 ships with an aggregate displacement of 182,800 metric tons (Andrea Doria, Caio Duilio, Conte Di Cavour, Giulio Cesare, Leonardo Da Vinci, Dante Alighieri, Roma, Napoli, Vittorio Emanuele and Regina Elena).
Italy would still have a quota of 175,000 tons, which was enough for five ships of 35,000 tons. However, Italy wasn't allowed to build 70,000 tons of new battleships before the treaty expired because she had the Caracciolo class. Therefore Italy won't be able to lay down Littorio and Vittorio Vento in 1934.